Conversation with my eldest:
Me: Hey, were you okay last night? You were so quiet after the movie, I was wondering if I had somehow hurt your feelings.
A: No, I was trying to see how long I could go without opening my mouth.
Me: Um. How did that come about?
A: Oh I just noticed at one point that it had been a long time since I'd opened my mouth so I decided to see how much longer I could make that last.